1865912921 has 2 divisors, whose sum is σ = 1865912922. Its totient is φ = 1865912920.

The previous prime is 1865912863. The next prime is 1865912941. The reversal of 1865912921 is 1292195681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1701150025 + 164762896 = 41245^2 + 12836^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1865912921 is a prime.

It is not a weakly prime, because it can be changed into another prime (1865912941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 932956460 + 932956461.

It is an arithmetic number, because the mean of its divisors is an integer number (932956461).

Almost surely, 2^1865912921 is an apocalyptic number.

It is an amenable number.

1865912921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1865912921 is an equidigital number, since it uses as much as digits as its factorization.

1865912921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 44.

The square root of 1865912921 is about 43196.2141975428. The cubic root of 1865912921 is about 1231.1107513217.

The spelling of 1865912921 in words is "one billion, eight hundred sixty-five million, nine hundred twelve thousand, nine hundred twenty-one".